Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules - Manual (Page 24)

24 Rockwell Automation Publication 1756-UM533C-EN-P - February 2011
Chapter 1 ControlLogix HART Analog I/O Modules
Module Scaling When using scaling, you change a quantity from one notation to another.
To scale a channel, choose two points along the module's operating range and
apply corresponding low and high unit values to those points.
Scaling lets you configure the module to return data to the controller in units that
match the quantity being measured. For example, the analog input module can
provide the temperature in degrees Celsius or the pressure in mbar. An analog
output module might have commanded values represented in % of stroke of a
valve. This makes it easier to use the values in your control program than by using
the raw signal value in mA.
Units like gallons, percent, mbar, psi, celsius, liters, and liters/minute are referred
to as Engineering Units.
For more information about scaling, see Scaling to Engineering Units on page 98 .